Scientists haven't found a direct link between the symptoms of headaches and general complaints and being near electromagnetic fields. Some speculate that it is a mental instead of a physical disorder

The explosive spread of electromagnetic fields across the world has undeniably spawned at least one disorder: electrosensitivity syndrome. Millions of people -- most of them in Europe -- say they suffer headaches, depression, nausea, rashes and other problems when they're too close to cellphones or other sources of EMFs. They've formed their own support groups, started their own newsletters and taken drastic steps to avoid EMFs, with some even wearing metallic clothing. A band of EMF "refugees" has moved to a valley in southern France to avoid radiation.

The list of victims includes Gro Harlem Brundtland, the former director-general of the World Health Organization. In 2002, when she still held her title, Brundtland told the BBC that she didn't allow cellphones in her office because the radiation gave her headaches.

In "Full Signal," a documentary that premiered at the 2009 Santa Fe Film Festival, a self-described sufferer of EMF poisoning says that if someone accidentally forgets to turn off a cellphone before entering her house, she starts to feel ill within a couple of hours. "After four hours I can't speak anymore," she says.

Alarming, yes, but such symptoms may not have much to do with electromagnetic fields. Even David Carpenter, a professor of environmental health sciences and biomedical sciences at the University at Albany, State University of New York, who often warns against the dangers of EMFs, isn't convinced that low-level radiation can cause such a wide range of symptoms. He believes that EMFs can cause cancer and possibly neurological disorders such as Alzheimer's and Lou Gehrig's disease, but there's no good evidence that cellphones can cause headaches and other vague complaints, he says. "I'm not sure electrosensitivity is real."

Many researchers have looked for a connection between EMFs and EMF sensitivity syndrome, but so far they've mostly come up empty. In one recent example, an English study of 48 self-described "electrosensitive" people and 132 "non-sensitive" people published online in January in the journal Environmental Health Perspectives found that all of the subjects had pretty much the same reaction to microwave radiation, which is to say no obvious reaction at all. The researchersspeculated that a fear of EMFs -- and not any physical issues -- might be the root cause of electrosensitivity.

A 2005 report from the World Health Organization -- Brundtland's former agency -- stated that people who believe they're sensitive to EMFs don't seem to have any special abilities to actually detect the fields. The report suggested that anxiety about EMFs could be the root cause of all of the symptoms.

"You have a whole population of people that are scared to death of electromagnetic fields," says Ken Foster, a professor of bioengineering at the University of Pennsylvania in Philadelphia who believes that low-level EMFs have little to no effect on human health. "People latch on to fears that mainstream science doesn't take seriously." He says electrosensitivity syndrome seems to be similar to multiple chemical sensitivity syndrome, a condition that most experts consider to be psychological.

A 2009 article in the journal PLoS ONE speculated that people who believe they're electrosensitive may have overactive distress signals in the brain. The researchers noted that cognitive behavioral therapy is often an effective treatment.